TY  - JOUR
A1  - Modak, Sujoy Kumar
A1  - Singleton, Douglas
T1  - Inflation with a graceful exit and entrance driven by Hawking radiation
JF  - Physical review : D, Particles, fields, gravitation, and cosmology
N2  - We present a model for cosmological inflation which has a natural "turn on'' and a natural "turn off'' mechanism. In our model inflation is driven by the Hawking-like radiation that occurs in Friedmann-Robertson-Walker (FRW) space-time. This Hawking-like radiation results in an effective negative pressure "fluid'' which leads to a rapid period of expansion in the very early Universe. As the Universe expands the FRW Hawking temperature decreases and the inflationary expansion turns off and makes a natural transition to the power-law expansion of a radiation dominated universe. The turn on mechanism is more speculative, but is based on the common hypothesis that in a quantum theory of gravity at very high temperatures/high densities Hawking radiation will stop. Applying this speculation to the very early Universe implies that the Hawking-like radiation of the FRW space-time will be turned off and therefore the inflation driven by this radiation will turn off.
Y1  - 2012
U6  - https://doi.org/10.1103/PhysRevD.86.123515
SN  - 1550-7998
VL  - 86
IS  - 12
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Kaeonikhom, Chakkrit
A1  - Singleton, Douglas
A1  - Sushkov, Sergey V.
A1  - Yongram, N.
T1  - Dynamics of Dirac-Born-Infeld dark energy interacting with dark matter
JF  - Physical review : D, Particles, fields, gravitation, and cosmology
N2  - We study the dynamics of Dirac-Born-Infeld (DBI) dark energy interacting with dark matter. The DBI dark energy model considered here has a scalar field with a nonstandard kinetic energy term, and has potential and brane tension that are power-law functions. The new feature considered here is an interaction between the DBI dark energy and dark matter through a phenomenological interaction between the DBI scalar field and the dark matter fluid. We analyze two different types of interactions between the DBI scalar field and the dark matter fluid. In particular we study the phase-space diagrams of and look for critical points of the phase space that are both stable and lead to accelerated, late-time expansion. In general we find that the interaction between the two dark components does not appear to give rise to late-time accelerated expansion. However, the interaction can make the critical points in the phase space of the system stable. Whether such stabilization occurs or not depends on the form of the interaction between the two dark components.
Y1  - 2012
U6  - https://doi.org/10.1103/PhysRevD.86.124049
SN  - 1550-7998
VL  - 86
IS  - 12
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Gündelman, Eduardo
A1  - Singleton, Douglas
A1  - Yongram, N.
T1  - A two measure model of dark energy and dark matter
JF  - Journal of cosmology and astroparticle physics
N2  - In this work we construct a unified model of dark energy and dark matter. This is done with the following three elements: a gravitating scalar field, phi with a non-conventional kinetic term, as in the string theory tachyon; an arbitrary potential, V (phi); two measures - a metric measure (root-g) and a non-metric measure (Phi). The model has two interesting features: (i) For potentials which are unstable and would give rise to tachyonic scalar field, this model can stabilize the scalar field. (ii) The form of the dark energy and dark matter that results from this model is fairly insensitive to the exact form of the scalar field potential.
KW  - modified gravity
KW  - dark matter theory
KW  - dark energy theory
Y1  - 2012
U6  - https://doi.org/10.1088/1475-7516/2012/11/044
SN  - 1475-7516
IS  - 11
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -